A sheet for forming a burned pattern comprising a ceramic green sheet and a pressure-sensitive adhesive layer formed thereon has been known (Examined Japanese Patent Publication No. 4-5258). This sheet is intended to be used in such a manner that information, e.g., a pattern, is imparted to the ceramic green sheet with a heat-resistant ink to form a label or the like and this sheet is provisionally bonded to an adherend through the pressure-sensitive adhesive layer and then burned.
As a result of the burning treatment, organic components such as an organic binder or a pressure-sensitive adhesive layer disappear and the ceramic green sheet becomes a burned object which is tenaciously adhered as a burned label to an adherend. Consequently, such a sheet for forming a burned pattern is suitable for use in, for example, forming a burned label having high durability, high heat resistance, etc., and can be advantageously used for, for example, controlling a production system in which many kinds of finished products, semifinished products, or parts each made of a metal, glass, burned ceramic, or the like are produced in small quantities.
However, the conventional sheet for forming a burned pattern had a problem that where the sheet is provisionally bonded to a glass product, e.g., a Braun tube, and baked by burning to give a burned label, etc., carbonaceous residues such as tar or carbon remain in a large amount, thereby decreasing the degree of coloration of the burned label, etc. The decrease in the degree of coloration particularly becomes the problem in the case that it is intended to impart a contrast of, e.g., white. Further, there has been another problem that the carbonaceous residues generate at the interface with an adherend and constitute a weak boundary layer, thereby decreasing the adhesion of the burned label or the like to the adherend.
An object of the present invention is to develop a sheet for forming a burned pattern which contains a small amount of carbonaceous residues due to burning treatment and can form a burned label or the like having, for example, excellent retention of a colored state, e.g., whiteness, and adhesion after burning to the adherend.
There is another problem that when the above-described sheet for forming a burned pattern is provisionally bonded to an adherend made of, e.g., a ceramic and then washed with water, that is, in the step for producing Braun tubes or the like, washing with water is conducted before applying a fluorescent substance, but in such a case, if the sheet for forming a burned pattern is washed with water without conducting preburning, water penetrates into the bonding interface to cause the sheet to peel off. Although such a problem can be avoided when the sheet for forming a burned pattern is preburned, there is a strong desire for elimination of the necessity of preburning in order to improve the production efficiency of Braun tubes or the like.